The main objective of this proposal is to genetically characterize baculoviruses which are currently produced as biological insecticides and are widely disseminated in the environment. Restriction endonuclease analysis, nucleotide sequence homology studies and general genetic techniques will be employed in an effort to (1) establish a precise identification procedure for baculoviruses or recombinant forms of these viruses, (2) determine if any sequence homology exists between baculoviruses and mammalian viruses, (3) isolate genetic mutants of these viruses to more adequately characterize the type and mode of viral infection and (4) establish these viruses as a model system for studies of host-virus interactions. These studies will provide further information concerning the safety of spraying these viruses as biological insecticides. The viruses and their pest hosts may provide a unique and comparatively safe animal virus system for studies involving recombinant DNA techniques.